import java.util.Scanner;
public class Test20230807 {
    public static int JieCheng(int a) {
        int j=1;
        for (int i = 1; i <= a; i++) {
            j*=i;
        }
        return j;
    }
    public static void main(String[] args){
Scanner scanner = new Scanner(System.in);
int a = scanner.nextInt();
int b = JieCheng(a);
System.out.println(b);
    }

}
